Global warming has resulted in decline in mountain glaciers and snow cover in both the hemispheres and this is projected to accelerate throughout the 21st century. This has led to a reduction in water availability and hydropower potential, thus changing the seasonal flow of rivers.The rise of the sea level under warming is inevitable. The coastal areas of India face a grave risk from the sea level rise, which causes severe floods. India is the most flood distressed country in the world after Bangladesh, accounting for 1/ 5th of the global deaths every year with 30 million people displaced from their homes yearly. Approximately 40 million hectares of the land is vulnerable to floods, with 8 million hectares affected by it. Unprecedented floods take place every year at one place or the other, with the most vulnerable states of India being Uttar Pradesh, Bihar, Assam, West Bengal, Gujarat, Odisha, Andhra Pradesh, Madhya Pradesh, Maharashtra, Punjab, and Jammu and Kashmir.Water pollution in Asia has long been a subject of concern, and the Ganges is one of the harder hit bodies of water from the effects of the industrial boom in the continent A report from the World Bank estimates that 20% of the contaminants in the river come from industrial emissions, and roughly one billion gallons of untreated sewage enter its waterways on a daily basis. Industrial wastes, mixtures of chemicals, and heavy metals are all discharged into the water and these are difficult to clean up. The domestic wastes from the households and sewages are constantly dumped into the river bodies. In addition to this, regular disposal of plastic bags and plastic objects, solid wastes, flowers, garlands, and animal washing are regularly contaminating the water with harmful pollutants. The water from rivers and lakes have become unhygienic posing serious threats to humans as well as the environment.Yamuna has become a garbage dump area with more than 57 % of Delhi’s waste thrown into it.According to the CSE, around 80% of Yamuna’s pollution is due to raw sewage. Ganga is considered to be the most polluted river in India. Approximately one billion litres of raw, untreated sewage is dumped into Ganga regularly.Ganga contains 60,000 faecal coliform bacteria per 100 ml, which is a threat to human health.The rise in temperature with no rainfall is also drying up the rivers and lakes. Uttar Pradesh and Bihar are reeling under drought due to climatic change. India’s initial National Communication to the United Nations Framework Convention (UNFCCC) on Climate Change projects that Luni- the west flowing river of Kutchh and Saurashtra are likely to experience acute physical water scarcity. The river basins of Mahi, Pennar, Sabarmati, and Tapi are also likely to experience constant water shortages.Jayanta Bandyopadhyay, Distinguished Fellow, Observer Research Foundation, Kolkata, said, “Water bodies are drying up during lean rainfall periods and overflowing during the monsoon. This is a signal of ecological instability at the watershed level. Protection of rivers is a misleading term. The question is how we can optimise the in-stream uses of rivers with the use of diverted flows. This needs an honest and comprehensive decision-making involving all stakeholders. Usually the marginal stakeholders do not get an opportunity to record their needs and priorities. The river basins as a whole need a mechanism for arriving at such a mechanism for allocation of water for diversion and in-stream uses. Depending on priorities, a river can be kept with pristine flow or dried up completely by transfers. The allocation of a percentage of flow, usually 10 or 15% as ‘environmental flow’ that will keep the ecosystem in full health and functioning, is a completely erroneous idea.”Climate-driven disturbances are also having profound impacts on coastal ecosystems, with many crucial habitat-forming species in sharp decline. One of the major reasons for the decline of marine population is the whooping number of oil spills around the world. Recently, two cargo ships collided off the Ennore coast in Chennai causing oil to spill into the sea. The spill has devastated Chennai’s beaches spreading 34 km till Vettuvankeni in the south, making patterns in the sand, adversely impacting the fishermen. Oil spills have been occurring frequently in every part of the world, destroying the marine ecosystem and polluting the environment severely. According to the US Department of Energy, 1.3 million gallons (4.9 million litres) of petroleum spill into the US waters from vessels and pipelines in a typical year. The most affected parts are the Gulf of Mexico (267 spills), the northeastern US (140 spills), the Mediterranean Sea (127 spills), the Persian Gulf (108 spills), and the North Sea (75 spills). This occurs mostly due to negligence, breakage of pipelines, and collision of ships or leakage of the underground storage tanks.The oil spill is the major reason for the extinction of marine population. Oil slicks, currently which are floating in the Gulf, affect wildlife by coating their bodies in the water-repelling gunk. Since it floats, all sorts of marine animals, even birds are affected. According to the Australian Maritime Safety Authority, fishes sometimes mistake the floating slick for food and are attracted to it. When birds’ feathers get coated with oil, they lose their ability to trap air and repel water thus unable to maintain body heat, which results in hypothermia. Marine animals, such as sea otters, which depend on their clean fur coats to stay warm, can also become hypothermic, according to the Oiled Wildlife Care Network. The oil sometimes clogs the blowholes of whales and dolphins, making it impossible for the animals to breathe properly, disrupting their ability to communicate.Oil spills often take a deadly toll on fish, shellfish, and other marine life, particularly if large numbers of fish eggs or larvae are exposed to the oil. The shrimp and oyster fisheries along the Louisiana coast were among the first casualties of the 2010 BP Deepwater Horizon offshore oil spill. Similarly, the Exxon Valdez oil spill destroyed billions of salmon and herring eggs.Oceans and marine population is not only threatened by oil spills. A UN report found that ocean acidification is up around 26% and more than half of the sharks and rays in the Mediterranean are at the verge of extinction. In 2016, with a population of only three, the Irrawaddy dolphin in Laos was declared “functionally extinct”. The announcement came after a World Wildlife Fund survey of Cambodia and Laos determined there were not enough mating pairs for the species to survive. The extinction is said to occur because of gill nets, a type of netting used by commercial fishermen that trap fish by their gills. Dolphins are caught in the nets and drown. Vaquita, or “Little cow” in Spanish, is the smallest species of porpoise, and the remaining few live in the Gulf of California. Vaquita are so rare that some people who live on the Gulf don’t believe they exist, according to a recent Vaquita documentary. A Conservation Biology acoustics survey found that there are only 60 left. Like the Irrawaddy dolphin, they are victims of gill net fishing. The situation is alarming now in many parts of the world. It is necessary that the world wakes up to the serious issue and takes mandatory steps.In India, the government has recently started the ‘Namami Gange Programme’, which is an Integrated Conservation Mission, approved as ‘Flagship Programme’ by the Union Government in June 2014 with budget outlay of`20,000 crore with the objective of abatement of pollution, conservation and rejuvenation of National River Ganga. It is not only the responsibility of the government but also individuals. If there is a ranking of countries in respect of observance of standards of sanitation and hygiene, one can be sure that India would figure close to the bottom. Blind religious faith and social practices in India are deteriorating the situation. Carcasses of cattle and other animals are disposed in the rivers. Dead bodies are cremated on the river banks. Partially burnt bodies are also flung into the river. All this is done as a matter of religious faith and in keeping with ancient rituals. Mass bathing in a river during religious festivals is another environmentally harmful practice. Studies have revealed that the biochemical oxygen demand (BOD) goes up drastically when thousands of people simultaneously take a ‘holy dip’. There is no culture without cleanliness. The customs and habits we are accustomed is at fault. The mindset and the mentality of the people need to be checked first. Bringing awareness among people is the first thing that should be focused immediately.